AR 15 break in process?

[Major03]

Disassemble your upper from your lower and take a picture of the feed ramps

 

[judah7]

Disassemble your upper from your lower and take a picture of the feed ramps

Best pictures I can get with cellphone.

 

[Biggfoot44]

Another vote for congealed Frog droppings . Clean it all off until firing pin and bolt move freely. Drop bolt carrier assembly into synthetic motor oil. ( I'm an individualist, and like Rotella T6 5w-40.)

 

[buellsfurn]

Id take it to Chad he is in Glen Burnie Great guy and knows his stuff. despite what you may have read hear he doesn't have a I'm God complex .

 

[judah7]

Id take it to Chad he is in Glen Burnie Great guy and knows his stuff. despite what you may have read hear he doesn't have a I'm God complex .

Haven't read anything about anyone, but I've reached out to him and another fellow member has reached out to me. I appreciate having the options.

 

[knightindullarmor]

Did you or anyone else d*ck with/replace the hammer spring?

Meaning is it a stock GI weight spring or a reduced weight spring?

Cuzz reduced weight and hard primers equals no Boom-Boom.

Outside of that, lube the ole girl up and give her another whirl.


PS: On-line reports say an AR needs at least a 3,000 round break-in period before they'll function correctly. Could be an urban legend though...

One of the springs in the lower parts kits can be installed backwards/upside down. Think it might be the aforementioned hammer spring. Worst part is that it will sometimes still function with the spring installed wrong and sometimes cause the hammer to not function correctly, which makes it hard to diagnose. I learned this lesson the hard way (read as... I installed the spring incorrectly, myself) the first time I built an AR. Worth checking it out.

 

[Major03]

Based on the pic of the brass I was expecting you to have an M4 cut receiver and a rifle cut barrel extension...which leads to feed issues.

But it looks like the pic shows a rifle receiver and either a rifle extension or an M4 extension...either of which should be fine.

I'm going with old lube jamming up the Bcg.

Lube it up and tell us how it goes

 

[mopar92]

Hey guys this is one of the rounds that was failure to feed, racked the gun back, gun fired, ejected the brass and then failure to feed. The round is clearly not going into the chamber at the right angle to damage the case like this right?

Obvious case of excessive bolt carrier drag. Those two somewhat opposing marks are the bolt lugs smashing the top of the brass and shoving it forward. Thats why the round isn't chambering and when it chambers it doesn't fire. Bolt isn't going fast enough or far enough.

Don't worry about your feedramps. PMAGs sit higher in the gun above the feed ramp. That's one of the reasons they're so reliable, the round goes in much straighter vs older USGI designs.

 

[zoostation]

The one thing that gives me a bit of hope that this is an easy fix from gunked up lube is your relating how the gun is failing to fire when a round chambers, and not just misfeeding under the bolt. Though I would find it rare for a modern lube to act up that badly from a couple of years storage, I have to admit I have not used Froglube much so I am not terribly familiar with it. In any case something is slowing that BCG down. I'm hoping it's just congealed lube and not an out of spec upper or receiver extension dragging on the BCG, or a problem with the barrel extension/feed ramps resisting the advancing round. Or it could even be an out of spec BCG. You may want to take a look inside the receiver extension and see if there is a lot of scratching going on. Especially scratching on just on side that gets worse as you get closer to the upper receiver itself. That's a classic sign of an out of spec upper or extension forcing the BCG to drag at an angle.

 

[judah7]

The one thing that gives me a bit of hope that this is an easy fix from gunked up lube is your relating how the gun is failing to fire when a round chambers, and not just misfeeding under the bolt. Though I would find it rare for a modern lube to act up that badly from a couple of years storage, I have to admit I have not used Froglube much so I am not terribly familiar with it. In any case something is slowing that BCG down. I'm hoping it's just congealed lube and not an out of spec upper or receiver extension dragging on the BCG, or a problem with the barrel extension/feed ramps resisting the advancing round. Or it could even be an out of spec BCG. You may want to take a look inside the receiver extension and see if there is a lot of scratching going on. Especially scratching on just on side that gets worse as you get closer to the upper receiver itself. That's a classic sign of an out of spec upper or extension forcing the BCG to drag at an angle.

From the pictures here on page 4 can you see any abnormal scratches?

 

[judah7]

Obvious case of excessive bolt carrier drag. Those two somewhat opposing marks are the bolt lugs smashing the top of the brass and shoving it forward. Thats why the round isn't chambering and when it chambers it doesn't fire. Bolt isn't going fast enough or far enough.

Don't worry about your feedramps. PMAGs sit higher in the gun above the feed ramp. That's one of the reasons they're so reliable, the round goes in much straighter vs older USGI designs.

What does the bolt lugs look like?

 

[mopar92]

What does the bolt lugs look like?

https://www.mdshooters.com/showpost.php?p=4740084&postcount=21

 

[bkuether]

I got three things out of this thread:

• New BCG not cleaned before use
• Frog lube left in for two years
• BCG wasn't greased and oiled.

Get a cleaning brush and get EVERYTHING out of the upper and star chamber. I use balistol, and it breaks up old gunk well.

Take apart the bcg, and same thing, scrub it inside and out, wipe it down and re-assemble

put some oil on the charging handle wear points.

Dip the BCG in motor oil as described by others, let drip off until it mostly stops, and put it back into the upper.

If you still aren't getting function then there is something wrong. A new BCG can be tight, but shouldn't keep the gun from functioning.

You can shoot it like that for a bit but don't go hardcore. The grease keeps the wear down. Trust us on this!

 

[judah7]

Yeah seems like the consensus believes I screwed up by just throwing some frog lube on a new bcg and slapping it in, then not touching it for a couple year's. I can see how that could be problematic now, just didn't think it could cause this type of frequent malfunctioning. I'm hoping that's the issue because I desperately want to be able to go through a magazine without 80% failure.

I'm going to shoot it later today and if it fails im going to meet up with a member and get hands on assistance.

Thanks for all the support, you guys are great.

 

[dist1646]

In addition to lubrication, check the ejector plunger while you are at it. The edges look to be pretty square and it may be protruding just a bit too much, possibly catching the base of the case when the round is being fed into the chamber. That will also cause the case to bind on the barrel extension feed ramps when the round is being chambered. The case will look just like it does in the picture posted. Usually, removing the ejector plunger and rounding the edge slightly will cure that issue.

 

[Biggfoot44]

Ballistol is good stuff.

For pure removal of gunk, brake cleaner . Spray until runs clean, then let residual evaporate. Then lubricate.

Brake cleaner will remove all traces of lubricant, so be sure to lubricate well.

 

[zoostation]

From the pictures here on page 4 can you see any abnormal scratches?

You would need to actually look down inside the receiver extension tube with a light after removing the spring and buffer to possibly see what I am describing.

I hope it is just gunky lube but the more I re-read the IP the more I am suspicious of that BCG being an issue.

 

[Biff_N]

March 31st now...

Sent from my SM-T210R using Tapatalk

Thanks. I was trying to save them a trip out this afternoon only to find it closed.

 

[judah7]

Okay after cleaning and lubricating the BCG I took the gun out today and first thing I did was rack it of course, I then took the magazine out to see if it would eject the round since it didn't want to do it before and it actually worked.

I then put the magazine back in and racked another round in and fired the gun, it went boom, ejected the shell and then failure to feed. I clear the jam and rack it again, fire the gun (boom) failure to eject and a round is jammed because it has nowhere to go. I take the magazine out again, rack it back to get the round out and it wouldn't eject.... I had to stick my finver nail in there to slide the empty shell out of the chamber.

I will say this though the failure to ejects didn't happen as much today but it still happened way too often, the failure to feeds were about the same. I didn't have many trigger pulls and no boom though.

So its official im going to have to link up with a member who reached out and has more expertise than I do to help me get it right.

Part of me feels like I have a faulty BCG because I did my research and nobody has had these kind of issues with there NFA lower and radical upper.

 

[judah7]

Moral of the story is it performed a little better but still 100% unacceptable.